The central role of the Neuropathology and Tissue Culture Core Facility is to assist the overall objectives of this Program Project to determine the different molecular pathways involved in the development of HIV-1 Encephalopathy. The Core will furnish the participants of the Program Project with surgical and autopsy brain tissue material from HIV-1 infected patients diagnosed with HIV- 1 Encephalopathy, as well as brains from HIV-1 infected individuals with no CNS involvement and normal control brains. In close collaboration with Projects 1,2 and 3, we will perform histological and immunohistochemical analysis, including double labeling, of viral proteins, cellular markers, and various cellular regulatory factors. The Neuropathology and Tissue Culture Core Facility will provide highly purified cultures of human fetal microglia, astrocytes, and neurons on demand. Primary cultures of neurons will also be prepared from rat and mouse hippocampus for the proposed studies. The established cell lines, PC12 and P19 will be maintained, cultured, and distributed to the projects. Also, Conditioned Media from HIV-1 infected cells will be prepared for use by the individual projects. Through this scientific core, we will ensure the efficient distribution of essential resources to all three projects and uniform evaluation of histological and immunohistochemical data while maintaining the highest level of quality control.